As a method of improving the efficiency of a compressor, the diameter of a suction hole may be increased to reduce the loss of suction pressure. However, the increase in the diameter of the suction hole is limited, because the suction hole is provided in the proximity of a vane groove and a spring hole provided in a cylinder to increase the displacement volume of the compressor.
Patent Literature 1 describes a configuration in which the diameter of the suction hole is made larger on the inner circumferential side of the cylinder than that on the outer circumferential side of the cylinder to reduce suction resistance.
Patent Literature 2 describes a configuration in which the suction hole is provided so that the central axis of the suction hole is inclined toward a tangent to the inner circumferential surface of a cylinder chamber to reduce flow resistance of suctioned gas. The literature further describes a configuration in which the suction hole is bent so that the central axis of the suction hole on the side connected to a suction pipe is directed to the center of the cylinder, and that the central axis of the suction hole on the side of the cylinder chamber is inclined toward the tangent to the inner circumferential surface of the cylinder chamber.